摘要 吉林省集安活龙金矿区位于一巨大剪切带中,强烈糜棱岩化,产生了Lister and Snoke(1984)所定义的Ⅰ和Ⅱ两类SC糜棱岩。依据两种主要糜棱面理S(Sm)与C的几何关系及局部发育的拉伸线理,初步确定了发生于中生代的两次剪切运动。含金石英脉(金矿体)均顺沿C面空间形成,当转入S时,则很快变薄消失。但S面大面积低品位金矿化现象表明,S面在含金流体渗透时曾起到通道作用。宏观上,含金石英脉集中分布于由接近平行的或交织的C面组成的、且排列较规则的构造带中,因C面通常倾角极缓,故构造带和相关的含金石英脉组呈一定间距出现于某些标高段内。金矿体的品位、厚度的稳定方位与S∧C交线方位接近,而且金矿体往往呈串珠状和透镜状顺此方位排列。
The Huolong Gold Mine in Ji’an city, Jilin province, was taken as an example for discussion. Tectonically, the mine area was situated in a large shear zone in the Central Liaoning-Southern Jilin Proterozoic mobile belt. There were two types, namely, type-Ⅰ and type-Ⅱ, of S-C mylonites in the sense of Lister and Snoke(1984)in the area as a result of extensive mylonitization. Geometrical relationships between two main mylonitic foliations S(Sm)and C substantiated a non-coaxial strain regime of south-vergent shear movement, whereas the stretching lineation, even very local, might suggest a later one. These events were investigated to occur during Mesozoic. Gold-bearing quartz veins(ore bodies)always took up spaces within C surfaces, and gradually thinned out when they turned to S which was considered to act possibly as channels of fluid flow during fluid infiltration, evidenced by extensive low-grade mineralization throughout S distribution. Mesoscopically, gold-bearing quartz veins unexceptionally occurred in structural zones which were arranged regularly in sections and composed of C surfaces. As the C surfaces in the mine area were generally very gentle or nearly horizontal in dip, the structural zones and related groups of gold-bearing quartz veins usually appeared in the sections at certain elevations with nearly definite intervals. Further studies suggested the stable orientation of the grade as well as the thickness of the gold-bearing quartz veins being consistent with that of S∧C intersection; and furthermore, it was found that the veins were often in the pinch-and-swell and lens forms aligned with this orientation.